O Prâna, thou art Indra by thy light, thou art Rudra, as a protector; thou movest in the sky, thou art the sun, the lord of lights.

In plain words: The hymn praises Prana, the life-breath, as Indra, king of the gods, because of its brightness. It calls Prana Rudra, a fierce protecting god. It is also the sun, which moves across the sky and is the greatest of all lights.